Conventionally, there is known a semiconductor device having contained therein a semiconductor element in which a high frequency circuit is formed as an example of a semiconductor element. In such a semiconductor device, a conductor layer as an electromagnetic shielding structure is generally provided to surround the outer periphery of the semiconductor device for the purpose of shielding an electromagnetic wave emitted from the inside to the outside of the semiconductor device, or an electromagnetic wave applied from the outside to the inside of the semiconductor device (see Japanese Patent Laying-Open No. 2008-42152 (PTD 1), for example).
In a semiconductor device described in PTD 1, semiconductor elements are placed on a wiring board, and an insulating layer is provided to surround the upper portions of the semiconductor elements. Furthermore, a conductor layer is provided to surround the insulating layer. The wiring board, the insulating layer and the conductor layer have vertically shaped side surfaces. The lower end of the conductor layer is in contact with the wiring board.